Adjustable counterbore



Feb. 19, 1929. 1,702,485

0. SEVERSON ADJ US TABLE COUNTERBORE Filed Dec, 9, 1924 2 Sheets-Sheet 1 Svwewtoz Feb. 19, 1929. 4 1,702,485

w OJ SEVERSON ADJUSTABLE counmnaozis 7 Filed Dec. 9, 1924 Z'Bhgets-Sheet 2 avwentoz Patented Feb. 19, 1929.

UNITED STATES PATENT OFFICE.

OLE SEVERSON, OF SHELTON, CONNECTICUT, ASSIGNOR TO THE 0. K. TOOL COMPANY, INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

' ADJUSTABLE COUNTERBORE.

Application filed December 9, 1924. Serial- No. 754,740.

This invention deals with metal cutting tools and it aims, on the one hand, to overcome certain difficulties resulting from the reduction of size through wear and grinding,

5 and on the other hand, it seeks to accomplish certain improvements in respect to self-guiding features when the tool is to be arranged for counter-boring or counter-sinking opera tions.

Regarding the first consideration, it may be noted that heretofore various species of adjustable reamers have been proposed with the object of enabling worn teeth to be shifted into positions permitting additional grinding without loss of size but such adjustments have usually been accomplished at the sacrifice of rigidity and simplicity in the tool. The aim of this phase of the invention is to provide for-such an adjustment but to do so in such a way that the tool will virtually retain all of the rigidity of a solid onepiece construction, and will possess the advantages of an insertable tooth formation which admits of the use of superior metal in the cutting edges, and which from a structural standpoint will be of the utmost simplicity and will be free from all unnecessary elements.

Regarding the self-guiding feature, the object of this invention is to make provision for the use of a so-called pilot which will be detachable so as to permit pilots of different diameters to be used in accordance with the particular size of the hole or recess to be worked upon. It is of advantage, in adhering to the dictates of structural simplicity to use pilots having stems of standard size receivable in axial sockets in the end of the shaft. Since the head of the pilot should fit the hole being worked upon rather closely andsince it should turn in that hole, and

since thereby a considerable friction is often created, the stem of the pilot may be subjected to considerable torque-which would tend to twist it off if the shank was used as the medium for rotating the pilot as a unit with the tool. This difficulty is overcome by the present invention through the expedient of providing the head of the pilot with shoulders for abutment against rigid portions of the tool; the protruding side faces of the teeth being especially suitable for that purose. P Other objects and advantages will be in -end elevation of Fig. 1.

the'economies and also of of slots 2, 3, 4c, 5 vetc.,

formation A, which, in this instance:i 1 ge part indicated in the following description and in part rendered apparent therefrom in connection with the annexed drawings.

To enable others skilled in the art so fully to apprehend the underlying features hereof that they may embody the same in the various ways contemplated by this invention, drawings depicting a preferred typical construction have been annexed as apart of this disclosure and, in such drawings, like characters of reference denote corresponding parts throughout all the views of which:

Fig. 1 is a side-elevation of an adjustable counter-boring tool embodying all of the features of this invention. Fig. 2 is a bottom Fig. 3 is a side elevatlon partly in section with the teeth omitted, showing the pilot alone attached to the shank. Fig. 4 is a top elevation of the pilot itself. Fig. 5 is a bottom end elevation of the shank itself with both the pilot and the teeth omitted. Fig. 6 is a perspective of an isolated tooth and Fig. 7 is an enlarged elevation partly in section of a completely assembled tool.

Referring to the drawings, A denotes the body portion of the tool which in this instance assumesthe form of a shank having a conventional stem 1 adaptable for insertion in a taper-drill holder and having a head A constructed as will be presently described. B indicates one of a series of insertable teeth and C denotes a pilot.

When it is desired to have the adjustment previously indicated, the teeth are detachably inserted and this is accomplished by providing the body portion, A with a series speaking, extend radially when a peripheral series of cutting edges are to be desired. One face of each of these slots is preferably arranged in coincidence with a plane extending parallel with the axis of the tool and such faces. are each provided with a similar-cons a, a, a, a All accurate identity is preserved in all respects except that the conformations are successively displaced slightly (say .005 in other words, the pomts a, a, a", and a are progressively a few thousandths of an inch further from the center. The signifishown as a corrugation or series of ri III of an inch) away from the cans;

which figuratively 3 .11% of this characteristic is that if the ldentical tooth be inserted successively in each of tilie slots, it will protrude progressively furt er.

Referring to the tooth 18 shown by Fig. 6, its rear face is flat except for corrugations or conformations B which are the counterparts of those A provided by the body portion or shank. These corrugations or conformations are parallel (in this instance) with the axis, so that the end 7 of the tooth can be easily slipped into the open end of the slot and shifted parallel with the axis while the conformations A and B are interfitting.

For the purpose of cramping each tooth firmly in its socket, the front face 8 of each tooth is at an angle with the rear face so as to produce a wedge-like shape, and the front face 6 of each slot is tapered at the same angle with respect to the rear corrugated face. The slots are, as indicated by 9 preferably somewhat longer than the teeth to provide a sufficient degree of clearance and yield and the teeth are readily secured in place by driving them into the sockets in a direction parallel with the axis until the yield and the friction prevent further movement.

The peripheral edges as well as the end edges of the teeth may then be ground and sharpened and the tool used until the teeth become dull. Thereupon, by striking the protruding end edges 10 of the teeth, they may be driven out andvreplaced in the next adjacent sockets of the series which willres'ult in shifting each tooth except the last outwardly to the extent of the increment bet-ween thesuccessive conformations. The last tooth will then fall into the place of the first tooth and will be shifted a whole corrugation and in consequence it will protrude somewhat more than the others because the corrugations will usually be wider than the sum of the in crements. This extra protrusion of the last tooth could, of course, be ground off and the whole series ground down to the correct diameter and sharpened.

An important characteristic of this structure is that no extra fastening elements are necessary because the teeth hold themselves in by the wedging action and as the advance of the tooth is in a direction contrary to the wedging' action, the heavier the duty performed by the tool,the more surely will the teeth remain in place. For the purpose of chip clearance, it is desirable to provide a cir cumferential series of clearance grooves or gouges 11 and a corresponding series of end face grooves 12 as will be readily perceived from the drawings.

With respect to themounting of the pilots C, the body portion is provided with a cylindrical co-axial hole 13 adapted to receive a stem 14 which is concentric with the head C of the pilot C. For the purpose of holding this pilot against dropping out, a set screw 15 may be used but neither this set screw nor any portion of the stem 14 is used to compel the pilot to rotate as a unit with the tool. That is accomplished by providing the head C of the pilot with a series of shoulders 16 which overlap and hence will abut the side faces 8 of the ends of the teeth. The teeth thus act as propelling elements for the pilot and carry the torque necessary to cause it to rotate as a unit with the tool.

This construction has the pronounced advantage that pilots of various sizes for fitting any given hole can be readily inserted in the tool since the stems can be made small and of uniform size, and the head of the pilot'irrespective of its size can be driven without fail inasmuch as it interlocks with the protruding portions of the teeth themselves which are. of course, of high grade material and of sufficient strength to accomplish that work. Furthermore, the torque is distributed among all of the teeth and hence is not 'cen tralized on an It will thus be seen that this invention is well adapted for use either as a self-guiding tool alone or as an adjustable cutter tool alone,

' or as an adjustable-tooth self-guiding tool for counter-bore work.

Without further analysis, will so fully reveal the gist of thisinvention that others can, by applying current knowledge, readily adapt it for various utilizations by retaining one or more of the features that, from the standpoint of the prior art, fairly constitute essentialcharacteristics of either the generic or specific aspects of this invention, and, therefore, such adaptations should be, and are intended to be, comprehended within the meaning and range of equivalency of the following claims.

Having thus revealed this invention, I claim as new and desire to secure the following combinations and elements, or equivalents thereof, by Letters Patent of the United States:

1. In a counter-boring tool, the combination comprising a head portion; radial slots formed in said head portion, said slots having serrations formed in the sides thereof and the serrations in successive slots being set an additional amount away from the axis of the tool corresponding to an increment of the distance between two serrations; detachable cutting blades adapted to fit in the slots in said head and having serrations interfitting the serrations in said slots; and a pilot having shoulders for engaging protruding portions of said blades ing relatively to the tool.

2. A rotary metal cutting tool comprising a base portion providing a succession of sockets; a series of inserted cutting bits, each of said bits having a multiplicity of corrugations parallel with one of its cutting edges, and the successive sockets having interfitting cor rugations progressively offset from the axis by the foregoing to prevent it from turnof said tool and having serrations formed on one side thereof, the serrations in successive slots being set away from the axis of the tool an additional amount equalling a small increment of the distance between two serrations; and detachable longitudinally wedgeshaped cutting blades adapted to fit in said slots, each blade having serrations formed in one side thereof for enabling the setting of from the axis of the blades laterally away when moved the tool said small lncrement from one slot to the adjacent slot.

- rality of cutting 4. In a metal cutting tool, the combination comprising a base having a plurality of slots formed therein around its axis; and a plublades for insertion in said slots, each of said blades having parallel serrations formed on one side thereof for interfitting similar serrations formed in the adj acent wall of each of said slots permitting removal of the blade by movement along the serration, and the serrations formed in successive slots being offset from the axis an additional amount equallingv a small increment of the distance between two serrations.

5. 'A rotary cutting tool combining a body member; a series of blades openings therein; cutting blades shaped in accordance wit said openings adapted to be inserted therein; a series of similar formations on a face of each blade; interfitting formations on the ad lar interfitting each opening and the adjacent blade surface jacent wall of said body member, the formations on the said walls of successive openings being advanced an increment of the distance between two formations whereby may be progressively advanced in accordance therewith by insertion in succeeding slots.

6. A rotary cutting tool combining a body member; a series of blade openings therein; cutting blades adapted to fit in said openings, said openings and blades being tapered to form a wedging fit for said blades; a series of similar interfitting formations on a side wal of each opening and the adjacent blade sur face with the formations extending in the direction of the taper, the formations in each slot being ofiset with respect to the axis from the position in adjacent slots a small incre ment of the distance between two formations whereby the blade may be progressively advanced transverse to the taper by movement to succeeding slots.

7. A rotary cutting tool comprising a body member; a series of blade openings therein; cutting blades adapted to fit in said openings, said openings and blades being tapered in the direction of the axis of the tool to form a wedging fit for said blades; a series of simiformations on a side wall of extending in the direction of the taper, the formations in the successive slots beingdistanced from the axis by an additional amount equal to a fraction of the distance between two formations; and a detachable pilot coaxial with the tool and having openings rebit ends including radial shoulders adapted to bear against said cutter bit ends, said openings permitting variation of both the radial and axial position of said ceiving the cutter h blades.

In witness whereof, I have hereunto subscribed my name.

OLE SEV'ERSON.

the blade 

